Automotive type lead-acid batteries have interlaced positive and negative electrodes, also called plates. Each plate consists of special material, known as active material, supported on lead alloy grids. The active material is formed from lead oxide pastes which are processed to a firm, porous form.
In the preparation of plates for a lead-acid battery, a mixture is formed comprising oxides of lead, sulfuric acid, water, and various additives. Conventional processes for preparing negative electrodes entail handling quantities of sulfuric acid as part of the pasting material, and complex basic lead sulfate reactions resulting in little control over the chemistry of the paste which changes during the process.
Precursor paste containing the active material is applied to conductive lead grids and, using conventional methods, the freshly pasted plates are cured for several days, typically 4 days at controlled temperature and humidity, as shown in a typical prior art process schematically shown in FIG. 1. The curing steps of current processes are time consuming and often lead to irregular product quality due to the changing chemistry of the active material from paste preparation through pasting of grids and curing and during pickling reactions.
It is a general object of the invention to provide a new process for preparing electrodes which produces a more consistent product and which is less time consuming and more efficient.